Complex organo silicon compounds

ABSTRACT

A composition for use in the treatment of glass fibers and glass fibers treated therewith, wherein the composition is formulated to include an organo silicon compound in the form of an epoxy silane blended with an organo silicon compound containing a beta-chloroalkoxy group. The glass fibers treated with the composition can be used in the reinforcement of thermosetting resins and elastomeric materials.

This is a continuation-in-part of copending applications Ser. No.347,264 now U.S. Pat. No. 3899524 and Ser. No. 347,241 now U.S. Pat. No.3931266 both filed on Apr. 2, 1973.

This invention relates to size compositions, and more particularly tosize compositions for use in the treatment of glass fibers to improvethe bonding relationship between glass fibers and resinous plastics inthe manufacture of glass fiber reinforced plastics.

The term "glass fibers," as used herein, is intended to refer to andinclude (1) continuous fibers formed by rapid attenuation of hundreds ofstreams of molten glass and to strands formed when such continuous glassfiber filaments are gathered together as they are being formed; and toyarns and cords formed by plying and/or twisting a number of strandstogether, and to woven and non-woven fabrics which are formed of suchglass fiber strands, yarns or cords, and (2) discontinuous fibers formedby high pressure steam, air or other suitable attenuating force directedonto multiple streams of molten glass issuing from a glass meltingbushing or from an orifice containing spinner, and to yarns that areformed when such discontinuous fibers are gathered together to form asliver which is drafted into a yarn; and to woven and non-woven fabricsformed of such yarns of discontinuous fibers, and (3) combinations ofsuch continuous and discontinuous fibers in strands, yarns, cords andfabrics formed thereof.

It is now standard practice in the manufacture of glass fiber-reinforcedplastics to employ glass fibers which have been coated with an organosilicon compound in the form of an organo silane or its hydrolysisproducts (e.g., the corresponding silanols and/or polysiloxanes). Thenature of the organo silicon compound employed depends somewhat on theparticular plastic to be reinforced. For example, where the resin is apolyepoxide, the organo silicon compound is frequently an organo silanecontaining an epoxy group ##STR1## where x is an integer from 2 to 5 andR is an alkyl group containing 1 to 5 carbon atoms, or the correspondinghydrolysis products thereof. Where the resin is a polyester, the organosilicon compound frequently contains ethylenic unsaturation; the silanecan be

    CH.sub.2 =CH-Si(OR).sub.3                                  ( 2)

or more preferably ##STR2## wherein R₁ is hydrogen or methyl.

While such silanes as well as their hydrolysis products are quiteeffective in promoting a secure bond between glass fibers andthermosetting plastics, they are quite expensive and therefore provide asignificant contribution to the overall cost of manufacture of glassfiber reinforced plastics. Numerous attempts have been made to reducethe cost of such silanes, usually by replacing a portion of the epoxy-oracryloxyalkylsilanes with a less expensive silane. In U.S. Pat. No.3,702,783 there is described a size composition which is formulated tocontain a glycidoxyalkyl silane of the type described above and amethyltrialkoxy silane. However, the methyltrialkoxy silane is notsignificantly less expensive than the glycidoxyalkyl silane and,consequently, the organo silicon compounds proposed by the foregoingpatent represent only marginal savings.

It is accordingly an object of the present invention to provide a sizecomposition for use in the treatment of glass fibers to promote a securebonding relationship between glass fibers and organic resins.

It is a more specific object of the invention to provide a sizecomposition for use in the treatment of glass fibers for use asreinforcement for resinous plastics.

It is another object of the invention to provide glass fibers treatedwith the composition of this invention for use as reinforcement forplastics.

The concepts of the present invention reside in glass fibers which havebeen sized, preferably as they are formed, with a size compositionformulated to include as the essential components an epoxy silane and anorgano silicon compound characterized by one or more beta-haloalkoxygroups. ##STR3## wherein X is halogen. It has been found that glassfibers having such a size coating on the surfaces thereof can besecurely bonded to resinous plastics in the manufacture of glass fiberreinforced plastics.

As the epoxy silane, use can be made of epoxy silanes having the generalformula ##STR4## wherein x is an integer from 3 to 6 and R is loweralkyl (e.g., methyl, ethyl, propyl, isopropyl, etc.), or epoxy silanesof the formula ##SPC1##

wherein y is an integer from 2 to 4, or the corresponding hydrolysisproducts such as the corresponding silanols and/or polysiloxanes.

Representative epoxy silanes gamma-glycidoxypropyltrimethoxy silane,gamma-glycidoxypropyltriethoxy silane, delta-glycidoxybutyltrimethoxysilane, 3,4-epoxycyclohexyethyltrimethoxy silane, etc.

The organo silicon compounds having the beta-haloalkoxy group employedin the practice of the invention are those described in copendingapplications Ser. No. 347,264 and Ser. No. 347,241, both of which werefiled on Apr. 2, 1973, and the disclosures of which are incorporatedherein by reference.

As is described in the foregoing copending applications, the complexorgano silanes are prepared by reaction of various combinations ofepoxides with a halosilane, and preferably a silicon tetrahalide.Epoxides used in the preparation of such silanes include alkylene oxidesand the following:

[1] Epoxides of the formula ##STR5## wherein R₂ is an aryl group such asphenyl or phenyl substituted with an amino group, a halogen group, analkyl group; alkyl containing 1 to 20 carbon atoms and substitutedderivatives thereof; an alkenyl group containing 2 to 8 carbon atoms(e.g., vinyl, allyl, etc.); styrene oxide; a group having the formula##STR6## wherein R' is hydrogen or methyl. Illustrative of such epoxidesare phenyl glycidyl ether, cresyl glycidyl ether, allyl glycidyl ether,glycidyl acrylate, glycidyl methacrylate, a mixture of n-octyl andn-decyl glycidyl ethers (Epoxide No. 7 from Procter and Gamble) and amixture of n-dodecyl and n-tetradecyl glycidyl ethers (Epoxide No. 8from Procter and Gamble). [2] Epoxides of the formula ##STR7## whereinR₃ is a divalent organic radical such as alkylene containing 1 to 10carbon atoms; alkylene-oxyalkylene containing 2 to 20 carbons;oxyalkyleneoxy containing 1 to 10 carbon atoms;oxyalkylene-oxyalkyleneoxy containing 2 to 20 carbon atoms; divalentaromatic groups such as a group of the formula ##SPC2##

A number of such epoxides are commercially avialable from Dow and Cibaand include the following: ##STR8## ##SPC3## [3] Cycloalkane epoxides,including the following: ##SPC4## ##SPC5##

In accordance with one embodiment of copending application Ser. No.347,264, the organo silicon compounds are prepared by reaction of from 1to 3 epoxide equivalents of the alkylene oxide and at least 0.5 and upto 3 epoxide equivalents of the epoxide containing a functional groupper mole of the silicon tetrahalide. As used herein, the term "epoxideequivalent" refers to the number of moles of the epoxide times thenumber of epoxide groups per molecule. Thus, this reaction may beillustrated by the following: ##STR9## wherein X represent halogen, R₄is hydrogen or C₁ to C₄ alkyl (e.g., methyl, ethyl, propyl, etc.), andR₅ is hydrogen or C₁ to C₄ alkyl, and preferably hydrogen, a representsthe epoxide equivalent of the alkylene oxide and b represents theepoxide equivalent of the epoxide containing a functional group##STR10## In actual practice, the reaction product produced is a mixtureof compounds which can be utilized as such without the need to separatespecific compounds contained in the reaction product.

However, compounds contained in the reaction mixture can be, if desired,separated from the mixture by known techniques, such as fractionaldistillation, liquid chromatography, etc., to yield the substantiallypure compounds. Such compounds frequently depend upon the epoxideequivalents employed, that is, the values of "a" and "b". For example,when the reaction mixture contains about 2 to 3 epoxide equivalents ofthe alkylene oxide and about 1 to 2 epoxide equivalents of the epoxidecontaining the functional group, the reaction product includes thefollowing compounds: ##STR11## wherein X is an integer from 2 to 3 and yis an integer from 1 to 2, and ##STR12## wherein x is 3 and y is 1 andwhere X, R₃ and R₄ are as described above, as well as the correspondingderivatives where the epoxide is a cyclohexane epoxide.

Where the epoxide containing the functional group includes two or moreepoxide groups, it is generally preferred that the equivalents of thealkylene oxide a be at least 2.2 and preferably at least 2.5 to avoidpolymer formation which leads to gelling of the reaction product.

In preparing the reaction mixtures of the present invention, thereactants are contacted in the liquid phase. An inert organic solventcan be employed, if desired, but is not essential to the practice of theinvention. The reaction temperature is not critical as the reactiongenerally takes place spontaneously and evolves heat. Best results areusually achieved when the reaction temperature is maintained below 100°C, such as within the range of 0° to 100° C.

When the epoxide containing the functional group as described abovecontains two or more epoxide groups, it is frequently preferred that thealkylene oxide be added to the halosilane prior to the time that thediepoxide is added to the reaction mixture. This procedure has theadvantage that the reaction of alkylene oxide with the silicontetrahalide is quite exothermic and thus raises the temperature of thereaction medium to a level suitable for addition of the epoxidecontaining the functional grouping.

Where the epoxide containing the functional group is a monoepoxide, thealkylene oxide or the monoepoxide can be added to the reaction mixturebefore the other, or they may be added simultaneously.

Where the reaction mixture contains two or more equivalents of anepoxide containing two or more epoxide groups per molecule, the reactionproduct includes compounds in which one of the epoxide groups in thefunctional epoxide remains unreacted with the silicon tetrahalide. Forexample, when the functional epoxide is one of those defined by [3]above, the reaction ##STR13## where R₃, R₄ and X are as described above.

In accordance with yet another embodiment of the invention, thehalosilane employed in the reaction can contain one or more organogroups attached directly to the silicon atom through a carbon-to-siliconbond. In the preferred practice of this embodiment of the invention, thehalosilane is of the formula

    (R.sub.7).sub.n SiX.sub.(4-n)                              ( 26)

wherein R₇ is an organic group containing 1 to 20 carbon atoms, n is aninteger from 1 to 2 and X is halogen and preferably chlorine or bromine.

R₇ is preferably alkyl containing 1 to 20, and preferably 1 to 6 carbonatoms (e.g., methyl, ethyl, propyl, isopropyl, lauryl, etc.); alkenylcontaining 2 to 20 and preferably 2 to 6 carbon atoms (e.g., vinyl,allyl, 3-butenyl, 4-pentenyl, etc.), cycloalkyl, such as cyclopentyl,cyclohexyl, etc., phenyl, as well as substituted derivatives thereof.

Where the organo halosilanes described above are reacted with analkylene oxide and an epoxide containing a functional group as describedabove, it is preferred to employ from 1 to 2.5 epoxide equivalents ormoles of the alkylene oxide per mole of the halosilane and from 0.5 to 3epoxide equivalents of the epoxide containing the functional group permole of the halosilane. Where the latter epoxide contains two epoxidegroups and n = 1, it is desirable to employ at least 1.2 and preferablyat least 1.5 epoxide equivalents of the alkylene oxide to minimize gelformation.

As is the case in the embodiments described above, the reaction productis usually in the form of a mixture of compounds. However, compoundswhich can be separated from the reaction products include: ##STR14##where R₇, R₄, R₂ and X are as described above and e is an integer from 1to 2, and f is an integer from 1 to 2, with the total of e and f beingequal to 3 where n is 1, and to 2 where n is 2; ##STR15## and/or

If desired, in the practice of this embodiment of the invention, thereaction can be carried out using a monoepoxide containing a functionalgroup alone. This reaction frequently produces specific compounds butcan also result in mixtures. Compounds produced include the followingtypes: ##STR16##

Representative of specific compounds include the following: ##STR17##(CH₂ =CHSiCl₃ 1 mole; allyl glycidyl ether 3 epoxide equivalents)##STR18## (CH₂ =CHSiCl₃ 1 mole; glycidyl acrylate 3 epoxide equivalents)

In accordance with one embodiment of copending application Ser. No.347,241, the organo silicon compounds are prepared by reaction of from 1to 3 epoxide equivalents of the monoepoxide and at least 0.5 and up to 3epoxide equivalents of another epoxide containing a functional group permole of the silicon tetrahalide. As used herein, the term "epoxideequivalent" refers to the number of moles of the epoxide times thenumber of epoxide groups per molecule.

For example, use can be made of a monoepoxide containing anotherfunctional group and a diepoxide as described above. This reaction canbe illustrated by way of the following equations: ##STR19## and##STR20## wherein X represents halogen, a represents the epoxideequivalent of the monoepoxide and b represents the epoxide equivalent ofthe diepoxide. In actual practice, the reaction product produced is amixture of compounds which can be utilized as such without the need toseparate specific compounds contained in the reaction product.

However, compounds contained in the reaction mixture can be, if desired,separated from the mixture by known techniques such as fractionaldistillation, liquid chromatography, etc., to yield substantially purecompounds.

It has been found that in the reaction mixture, a should be at least2.2, and preferably at least 2.5, to avoid polymer formation whichcauses gelling of the product. Thus, a is within the range of 2.2 to 3.5and b is within the range of 0.5 to 1.8. It has also been found thatwhere the reaction mixture contains 2 or more epoxide equivalents of thediepoxide, the compounds which predominate in the reaction mixture havethe general formula ##STR21## wherein c is within the range of 2.0 to 3and d is within the range of 1 to 2.0. Most frequently, c is 3 and d is1.

Where, however, use is made of less than 2 epoxide equivalents of thediepoxide, the product of the reaction includes compounds containing nofree epoxy groups; these compounds have the general formula ##STR22##

It will be observed that in all of the compounds specifically describedabove, each bond to the silicon atom contains a beta-haloalkoxy group.As indicated above, it is believed that such groupings impart improvedstability to the compounds.

In accordance with another concept, the reaction is carried out with 0.5to 2.5 moles of an alkylene oxide in addition to 0.5 to 2.5 epoxideequivalents of monoepoxide and the diepoxide. In this embodiment of theinvention, the alkylene oxide reacts with the halosilane in a similarmanner to form a beta-haloalkoxy group attached directly to the siliconatom. This reaction can proceed in two ways, depending upon the amountof diepoxide employed. Thus, where the amount of the diepoxide is lessthan two epoxide equivalents, the reaction proceeds as follows:##STR23## where e and g are each integers from 1 to 2 and f is 1, and R₄is hydrogen or C₁ to C₆ alkyl (e.g., methyl, ethyl, propyl, etc.).

As with the embodiment described above, the reaction product of theabove is a mixture which can be used as such or, if desired, thepredominant compounds having the formula stated above can be separatedfrom the reaction mixture.

Another group of compounds which can be employed in the practice of theinvention include compounds prepared by reaction of substantiallystoichiometric amounts of a silicon tetrahalide and an epoxide (9) asdescribed above, preferably an epoxide containing ethylenicunsaturation. Preferred epoxides are those of the formula ##STR24##where R₈ is C₂ to C₈ alkenyl (e.g., alkyl, vinyl, etc.), or a group##STR25## wherein R' is as described above.

These compounds have the formula ##STR26##

Representative compounds include the following ##STR27##

The combination of the epoxy silane and the betahaloalkoxy organosilicon compounds is formulated into a size composition for applicationto the glass fibers. The size composition is formulated with a solventor diluent such as an inert organic solvent or with water. For reasonsof economy, water is frequently preferred but volatile organic solventsmay also be employed if desired; suitable solvents include aliphaticaldehydes, aliphatic ketones, alcohols, etc.

The relative proportions of the epoxy silane and the beta-haloalkoxyorgano silicon compound can be varried within fairly wide ranges. Bestresults are usually obtained when the epoxy silane constitutes from 0.05to 2% by weight of the size composition and the beta-haloalkoxy organosilicon compound constitutes 0.5 to 3% by weight of the sizecomposition. It has been found that the weight ratio of the epoxy silaneto the beta-haloalkoxy organo silicon compound is within the range of0.05 to 1, and preferably 0.1 to 0.7. Since the epoxy silane is the moreexpensive component, the amount of the beta-haloalkoxy organo compoundusually exceeds the amount of the epoxy silane on a weight basis.

While it is not essential to the practice of the invention, it isfrequently preferred to formulate the size composition to include afilm-forming material. A variety of film-forming materials can be usedfor this purpose, including polyester resins, polyamide resins,polyolefin resins (e.g., polyethylene, polypropylene, etc.), polyepoxideresins, vinyl resins (e.g., polyvinyl chloride, polyvinyl acetate,polyvinyl alcohol, polyvinyl pyrrolidone, etc.), waxes, polybutadienes,partially dextrinized starches and others. Such film forming materialsare themselves well known to those skilled in the art and are describedin U.S. Pat. Nos. 2,931,739, 2,958,114, 3,040,413, 2,252,278, 3,424,608.Combinations of two or more of such film-forming materials can also beused.

The size composition employed in the practice of this invention can alsobe formulated to include any of a variety of wetting agents, glass fiberlubricants, etc., also well known to the art.

The resulting size composition can be used in the treatment of glassfibers for use as reinforcement of thermosetting and for thermoplasticresins as well as elastomeric materials in accordance with conventionaltechniques. It has been found that the combination of the epoxy silanesand the betahaloalkoxy organo silicon compounds containing ethylenicunsaturation are particularly well suited for use as a size for glassfibers for reinforcement of polyepoxide resins.

Having described the basic concepts of the invention, reference is nowmade to the following examples which are provided by way of illustrationand not be way of limitation of the practice of the invention in theformulation of size compositions and the use of such compositions in thetreatment of glass fibers.

EXAMPLE 1

Into a 1-liter, round bottom flask equipped with a stir bar,thermometer, reflux condenser and addition funnel, there is added 280.6cc (2.48 mole) of SiCl₄. Then, there is added with stirring and cooling519.4 cc of propylene oxide followed by 862 g (4.94 epoxide equivalents)of DER 332.

The reaction mixture is stirred overnight, and analysis reveals amixture of compounds including the compound ##SPC6##

EXAMPLE 2

Using the procedure described in Example 1, 3 moles of propylene oxideis reacted with 1 mole of SiCl₄, and the product of the reaction in turnis reacted with one epoxide equivalent of DER 332.

Analysis reveals a mixture of compounds, including the compound ##SPC7##

EXAMPLE 3

One mole of SiCl₄ is reacted with 2.5 moles of propylene oxide, and theproduct is reacted with 0.5 moles of Epoxide No. 7 and 1.0 epoxyequivalent of ERE 1359. The product is a mixture which contains thecompound ##SPC8##

EXAMPLE 4

Each of the foregoing reaction products of Examples 1 to 3 is tested ina size composition with gamma-glycidoxypropyltrimethoxy silane (A-187from Union Carbide).

The size compositions were formulated as follows

    ______________________________________                                        Test Size A                                                                   Polyepoxide-amine resin 1.5  %                                                Acetic Acid             0.13  %                                               A-187                   0.2  %                                                Reaction product of Example 1                                                                         0.83  %                                               Emulsifying agent (Triton X-100)                                                                      0.083 %                                               Water to 100%                                                                 Test Size B                                                                   Polyepoxide-amine resin 1.5  %                                                Acetic Acid             0.13  %                                               A-187                   0.2  %                                                Reaction product of Example 2                                                                         0.436 %                                               Emulsifying agent (Triton X-100)                                                                      0.044 %                                               Water to 100%                                                                 Test Size C                                                                   Polepoxide-amine resin  1.5  %                                                Acetic acid             0.13  %                                               A-187                   0.2  %                                                Reaction product of Example 3                                                                         0.363 %                                               Emulsifying agent (Triton X-100)                                                                      0.036 %                                               Water to 100%                                                                 ______________________________________                                    

The polyepoxide-amine resin is a polyepoxide film former, and isdescribed in U.S. Pat. No. 3,449,281.

Each of the test size compositions A,B and C is applied to glass fibersas they are formed in the same manner. The coated glass fibers (in theform of slivers) are employed as reinforcement in standard polyepoxidetest rods, which are then tested to determine their strength, in a drystate and after having been contacted with boiling water for 24 hours. Acontrol size was also tested in the same manner; it was formulated

                  Control Size                                                    ______________________________________                                        Polyepoxide-amine resin                                                                            1.5%                                                     Acetic acid          0.13%                                                    A-187                0.4%                                                     Water to 100%                                                                 ______________________________________                                    

In each of test sizes A, B and C, half of the A-187 is replaced by anequivalent molar amount of the reaction products of each of Examples 1to 3.

The results of the tests are shown in the following table:

                  Table I                                                         ______________________________________                                        Silane  B-haloalkoxy                                                                             Dry shear strength                                                                         Wet shear strength                            A-187   compound   psi ×10.sup.3                                                                        psi ×10.sup.3                           ______________________________________                                        0.4% A-187                                                                            --         8.52         6.50                                          0.2% A-187                                                                            0.83% Ex. 1                                                                              9.27         7.73                                          0.2% A-187                                                                            0.436% Ex. 2                                                                             8.18         6.56                                          0.2% A-187                                                                            0.363% Ex. 3                                                                             10.12        8.27                                          ______________________________________                                    

As shown by the foregoing data, the use of β-haloalkoxy compounds incombination with A-187 is at least equal to A-187 alone, and generallysuperior thereto, as coupling agents for bonding glass fibers topolyepoxide plastics.

EXAMPLE 5

An organo silane is prepared by placing 127.4 g (0.75 mole) of SiCl₄ ina reaction flask, and then adding 87.1 g (1.5 mole) of propylene oxideand 171.1 g (1.5 mole) of allyl glycidyl ether. The product of thereaction is found to be a mixture which includes the compound ##STR28##

EXAMPLE 6

One mole of SiCl₄ is reacted sequentially with 2.5 moles of propyleneoxide, 0.5 mole of allyl glycidyl ether and 1 epoxide equivalent of DER332. The product is a mixture which includes the compound ##SPC9##

EXAMPLE 7

One mole of SiCl₄ is reacted with 2 moles of propylene oxide and 2 molesof glycidyl acrylate. The reaction mixture produced is found to containthe compound ##STR29##

EXAMPLE 8

One mole of SiCl₄ is reacted with 3 moles of propylene oxide and 1 moleof glycidyl acrylate. The product, a mixture, contains the compound##STR30##

EXAMPLE 9

Using the procedure of Example 1, 1 mole of SiCl₄ is reacted with 2moles of propylene oxide, 1 mole of glycidyl methacrylate and 1 epoxyequivalent of ERE 1359. The product includes ##SPC10##

EXAMPLE 10

One mole of SiCl₄ is reacted with 2 moles of propylene oxide, 1 mole ofglycidyl methacrylate and 1 epoxy equivalent of DER 332. The mixtureforming the product includes the compound ##SPC11##

EXAMPLE 11

One mole of SiCl₄ is reacted with 2 moles of propylene oxide, 1 mole ofglycidyl acrylate and 1 epoxy equivalent of ERE 1359. The mixtureresulting includes the compound ##SPC12##

EXAMPLE 12

One mole of SiCl₄ is reacted with 2 moles of propylene oxide, 1 mole ofallyl glycidyl ether and 1 epoxide equivalent of ERE 1359. The mixtureproduced includes the compound ##SPC13##

EXAMPLE 13

One mole of SiCl₄ is reacted with 2 moles of propylene oxide, 1 mole ofglycidyl acrylate and 1 epoxy equivalent of DER 332. The productincludes the compound ##SPC14##

EXAMPLE 14

One mole of SiCl₄ is reacted with 2 moles of propylene oxide, 1 mole ofglycidyl acrylate and 1 epoxide equivalent of ERL 4206. The mixtureforming the product includes the compound ##SPC15##

EXAMPLE 15

One mole of SiCl₄ is reacted with 2 moles of propylene oxide, 1 mole ofallyl glycidyl ether and 1 epoxy equivalent of ERL 4206. The productincludes ##SPC16##

In the preparation of each of the foregoing beta-haloalkoxy compounds,the reactants are added sequentially to the SiCl₄ in the order indicatedin each of the examples.

EXAMPLE 16

Using the procedure described in Example 1, one mole of vinyltrichlorosilane is reacted with 2 moles of propylene oxide and 1 mole ofglycidyl methacrylate. The product of the reaction is found to containthe compound ##STR31##

The reaction product is formulated into the following size composition:

    ______________________________________                                        Reaction product of any of Examples 5-16                                                                0.41%                                               Δ-glycidoxybutyltriethoxy silane                                                                  0.25%                                               Water to 100%                                                                 ______________________________________                                    

The above composition can be applied to glass fibers to form a coatingthereon as described above; the fibers are well suited for use asreinforcement for thermosetting resins.

In the final reinforced resin, the thermosetting resin constitutes acontinuous phase in which the coated glass fiber reinforcements aredistributed. The glass fibers can be in the form of chopped fibers,woven or non-woven mats, slivers, strands, etc. The coating on the glassfiber surfaces operates to establish a secure bonding relationshipbetween the glass fibers and the resin.

It will be understood that various changes and modifications can be madein the details of procedure, formulation and use without departing fromthe spirit of the invention, especially as defined in the followingclaims.

We claim:
 1. Glass fibers having a thin size coating thereon, saidcoating comprising an organo silane selected from the group consistingof a compound having the formula ##EQU1## and a compound having theformula ##SPC17##wherein x is an integer from 3 to 6, y is an integerfrom 2 to 4 and R is alkyl and the hydrolysis products thereof, and anorgano silicon compound prepared by reaction of (1) a halosilaneselected from the group consisting of a tetrahalosilane and a halosilaneof the formula

    (R.sub.7).sub.n SiX.sub.4-n

wherein R₇ is an organic group containing 1 to 20 carbon atoms, n is aninteger from 1 to 2 and X is halogen, (2) a monoepoxide selected fromthe group consisting of an alkylene oxide, a functional epoxide havingthe formula ##EQU2## wherein R₂ is selected from the group consisting ofaryl, alkyl, alkenyl and a group having the formula ##EQU3## where R' ishydrogen or methyl, and combinations thereof, and (3) a diepoxideselected from the group consisting of an epoxide of the formula ##EQU4##wherein R₃ is a divalent organic group and a cycloalkane diepoxide, with(2) being reacted in a ratio of 1 to 3 epoxide equivalents per mole of(1) and (3) being reacted in a ratio of 0.5 to 3 epoxide equivalents permole of (1).
 2. Glass fibers as defined in claim 1 wherein (2) isreacted in a ratio of at least 2.2 epoxide equivalents per mole of (1).3. Glass fibers as defined in claim 1 wherein the halosilane is atetrahalosilane.
 4. Glass fibers as defined in claim 1 wherein thesilane is a gamma-glycidoxypropyltrialkoxy silane.
 5. Glass fibers asdefined in claim 1 wherein (3) is a diepoxide selected from the groupconsisting of an epoxide having the formula ##SPC18##and an epoxidehaving the formula ##SPC19##
 6. Glass fibers as defined in claim 1wherein the coating includes a film forming material.
 7. Glass fibershaving a thin size coating thereon, said coating comprising an organosilane selected from the group consisting of a compound having theformula ##STR32## and a compound having the formula ##SPC20##wherein xis an integer from 3 to 6, y is an integer from 2 to 4 and R is alkyland the hydrolysis products thereof, and an organo silicon compoundformed by reaction of (1) a silicon tetrahalide, (2) an alkylene oxide,and (3) a diepoxide of the formula ##STR33## wherein R₃ is a divalentorganic group, with (2) being reacted in a ratio of 0.5 to 2.5 epoxideequivalents per mole of the silicon tetrahalide, and (4) being reactedin a ratio of 0.5 to 3 epoxide equivalents.
 8. Glass fibers as definedin claim 7 wherein the diepoxide has the formula ##SPC21##
 9. Glassfibers as defined in claim 7 wherein the diepoxide has the formula##SPC22##
 10. Glass fibers as defined in claim 7 wherein the ratio of(2) is at least 2.2 epoxide equivalents per mole of silicon tetrahalide.11. Glass fibers as defined in claim 7 wherein the silicon tetrahalideis silicon tetrachloride.
 12. Glass fibers as defined in claim 7 whereinthe silane is a gamma-glycidoxypropyltrialkoxy silane.
 13. Glass fibersas defined in claim 7 wherein the alkylene oxide is propylene oxide. 14.Glass fibers as defined in claim 7 wherein the coating includes apolyepoxide resin film-forming material.
 15. In a glass fiber reinforcedplastic material in which a thermosetting resin constitutes a continuousphase in which the glass fibers are distributed, the improvement in thebonding relationship between the glass fibers and the resin comprisingglass fibers as defined in claim
 1. 16. A reinforced plastic as definedin claim 15 wherein the resin is a polyepoxide resin.
 17. In a glassfiber reinforced plastic material in which a thermosetting resinconstitutes a continuous phase in which the glass fibers aredistributed, the improvement in the bonding relationship between theglass fibers and the resin comprising glass fibers as defined in claim7.
 18. A reinforced plastic as defined in claim 17 wherein the resin isa polyepoxide resin.
 19. In a glass fiber reinforced plastic material asdefined in claim 17 wherein the diepoxide has the formula ##SPC23## 20.In a glass fiber reinforced plastic material as defined in claim 17wherein the diepoxide has the formula ##SPC24##
 21. In a glass fiberreinforced plastic material as defined in claim 17 wherein the total ofthe ratios of (2) is at least 2.2 epoxide equivalents per mole ofsilicon tetrahalide.
 22. In a glass fiber reinforced plastic material asdefined in claim 17 wherein the silicon tetrahalide is silicontetrachloride.
 23. In a glass fiber reinforced plastic material asdefined in claim 17 wherein the silane is agamma-glycidoxypropyltrialkoxy silane.
 24. In a glass fiber reinforcedplastic material as defined in claim 17 wherein the alkylene oxide ispropylene oxide.
 25. Glass fibers having a thin size coating thereon,said coating comprising an organo silane selected from the groupconsisting of a compound having the formula ##STR34## and a compoundhaving the formula ##SPC25##wherein x is an integer from 3 to 6, y is aninteger from 2 to 4, and R is alkyl or hydrolysis products thereof, andan organo silicon compound prepared by reaction of (1) a halosilaneselected from the group consisting of a tetrahalosilane and a halosilaneof the formula

    (R.sub.7).sub.n SiX.sub.4-n

wherein R₇ is an organic group containing 1 to 20 carbon atoms, n is aninteger from 1 to 2, and X is halogen, (2) an alkylene oxide and (3) afunctional epoxide of the formula ##STR35## wherein R₂ is selected fromthe group consisting of aryl, alkyl, alkenyl and a group having theformula ##STR36## wherein R' is hydrogen or methyl, with the ratio of(2) being 1 to 3 epoxide equivalents per mole of (1) and the ratio of(3) being 0.5 to 3 epoxide equivalents per mole of (1).
 26. Glass fibersas defined in claim 25 wherein (1) is a tetrahalosilane.
 27. Glassfibers as defined in claim 25 wherein the functional epoxide is glycidylacrylate or methacrylate.
 28. Glass fibers as defined in claim 25wherein the coating includes a film-forming material.
 29. In a glassfiber reinforced plastic material in which a thermosetting resinconstitutes a continuous phase in which the glass fibers aredistributed, the improvement in the bonding relationship between theglass fibers and the resin comprising glass fibers as defined in claim25.
 30. In a reinforced plastic material as defined in claim 29 whereinthe resin is a polyepoxide resin.
 31. Glass fibers having a thin sizecoating thereon, said coating comprising an organo silane selected fromthe group consisting of a compound having the formula ##STR37## and acompound having the formula ##SPC26##and a organo silicon compoundhaving the formula ##STR38## wherein R₈ is alkenyl or a group of theformula ##STR39## wherein R' is hydrogen or methyl, and X is halogen.32. A glass fiber reinforced plastic product reinforced with glassfibers as defined in claim 31.